By JUAN FORERO

Published: November 19, 2005

SHE'S the Venezuelan government's most detested adversary, a young woman with a quick wit and machine-gun-fast delivery who often appears in Washington or Madrid to denounce what she calls the erosion of democracy under President Hugo Ch?z.

In a highly polarized country, Mar?Corina Machado has emerged as perhaps the most divisive figure after Mr. Ch?z, a woman who is either beloved or reviled.

Ms. Machado, 38, attractive and a fluent English speaker, is lionized by her allies in the opposition as a worldly sophisticate fighting for democracy. But she is demonized by the government, which characterizes her as a member of a corrupt elite that is doing the bidding of the much reviled Bush administration.

Ms. Machado does not hide her close relations with Washington, which has provided financial aid to S?e, the anti-Ch?z, election-monitoring organization she helps run. In May, she infuriated the government when she met with President Bush at the White House, and she further antagonized officials in September by announcing that S?e had received a fresh infusion of $107,000 from Washington.

Ms. Machado casts her role as that of a watchdog uncovering the electoral shenanigans she says Mr. Ch?z uses to consolidate his hold, a precarious job in Venezuela these days.

''You can push and push, but at some point they are going to get tired and say, 'It is time to get her off our backs,' '' Ms. Machado said.

That time arrived for Ms. Machado in September 2004. In a case that Human Rights Watch says is riddled with violations of due process, the attorney general's office charged her and three other S?e officials with treason and other crimes for having accepted American financing to mount a referendum last year asking voters whether they wished to remove Mr. Ch?z from the presidency.

Accepting prosecution arguments that S?e's work amounted to an effort to ''destroy the nation's republican form,'' a Venezuelan judge ruled in July that the four should face trial.

The trial is set for Dec. 6, and a conviction could carry a 16-year prison term. ''It was the first time I discovered what it was like to have my legs tremble,'' she said, recalling her interrogation before a prosecutor.

AFTER being charged last year, Ms. Machado, a divorced mother of three, sat down with her daughter, then 14, and told her of the dangers that lay ahead. She then sent the girl and her two younger brothers off to stay with their grandparents because of fears that pro-government fanatics could ransack the house.

''Tears rolled down my face,'' she recalled recently over a strong dose of Venezuelan coffee at a trendy cafe in a solidly anti-Ch?z neighborhood. ''My lawyer had worried that they'd show up at midnight looking for me.''

She then leaned across the table, slightly embarrassed, and said she did not want to present herself as a victim. ''I think that would be pathetic,'' she said. She has never been accosted, she said, and she drives around Caracas alone, with no bodyguards.

While one of the most visible public figures in Venezuela, Ms. Machado is sparing with details about her personal life, one of comfort and privilege.

She was the eldest of four girls growing up in a conservative, staunchly Catholic family. There was the elite Catholic girls' school in Caracas; the boarding school in Wellesley, Mass.; the trips to Europe; the occasional escapes from Venezuela's teeming capital to her family's airy mountain retreat.

''It was a childhood protected from contact with reality,'' she admits.

Many weekends were spent romping with a brood of cousins in a vast, rambling house in Caracas belonging to her grandmother, Ana Teresa Machado. That house also held the history of Venezuela, and Ms. Machado's grandmother had stories to tell of a wider world and of their forebears, who had literally helped write Venezuela's past.

One was Eduardo Blanco, Ms. Machado's great-great-grandfather, who published ''Heroic Venezuela'' in 1881, still a classic of independence-era history for Venezuelan children. Another was Armando Zuloaga Blanco, her great-uncle, who became a martyr for democracy when he was killed in a failed uprising in 1929 against the dictator Juan Vicente G?.

''I would sit down on my grandmother's knee and hear about our country's history,'' Ms. Machado said. ''It was all very much a part of growing up. She would tell me stories, and I would listen for hours.''

Now, it is Ms. Machado who is making history.

AT first, though, she followed in the footsteps of her father, Henrique Machado, studying engineering at Catholic University in Caracas. She married young and in 1990 began her career working to improve quality controls in an auto plant in Valencia.

Three years later, she was back in Caracas, having decided to join her mother in running a home for 140 abandoned and troubled children.

Her life took a turn in 2001. That was the year her marriage broke up, but also year three of Mr. Ch?z's rule, and Ms. Machado and her friends were growing worried.

She now says it was concern over ''tensions'' that prompted them to form S?e, with the purpose of mounting the referendum on Mr. Ch?z. ''The idea was not, how do we get rid of this government,'' Ms. Machado said. ''The idea was how do we resolve the profound social differences.''

That account, of S?e as an organization independent of other groups intent on removing Mr. Ch?z from office, does not squarely line up with history. S?e, in fact, earned the government's undying enmity when it loudly questioned the results of the August 2004 referendum, even though international observers said Mr. Ch?z had won handily.

The Ch?z camp also took a dim view of the fact that Ms. Machado was in the Miraflores Palace on the day in April 2002 when Pedro Carmona, an opposition businessman, installed an interim government just hours after Mr. Ch?z was overthrown in a coup.

With a sigh, Ms. Machado says that she and her mother were in the palace that day only to visit Mr. Carmona's wife, a family friend. ''I have a clear conscience,'' she said. ''There was no double meaning in what happened.''

In recent months, Ms. Machado has toned down her rhetoric on Mr. Ch?z.

She said she understood why so many Venezuelans support the populist government, which has showered the poor with social programs underwritten by a flood of oil money. ''We have to recognize the positive things that have been done,'' she said.

Still, she has not stopped criticizing the president, who she charges is increasingly intolerant. ''The intimidation has given us more reasons to keep working,'' she said. ''Our organization seeks to preserve citizens' rights, and the way to do that is by exercising those rights.''

Photo: MARÍA CORINA MACHADO (Photo by David Rochkind/Polaris, for The New York Times)